Accurate characterization of the physical properties of atmospheric hydrometeors is useful for a broad range of practical and scientific applications. For example, hydrometeor diameter-mass-fallspeed relationships are useful components of weather and climate numerical models used in forecasting. Also, snowflake shape and size has an influence on snowpack density, and thus can be used for analyzing skiing conditions and avalanche susceptibility. The range of possible particle shapes and sizes is extremely broad, and includes raindrops, dendritic snowflakes, aggregated forms, graupel, and hail, and generally includes sizes ranging in diameters from less than a millimeter to several centimeters. Hydrometeor properties that have attracted past scientific interest include three-dimensional shape and size, fall-speed, and rotational motions about the particle center of mass.
A wide variety of electro-optical and communications devices and methods have been developed for inspecting and analyzing hydrometeors. Such systems have attempted to characterize hydrometeor structures and relate crystalline forms to changes in atmospheric electromagnetic attenuation, fall velocity, density, etc. Viewing of hydrometeors generally may take place in the field. However, such devices configured for viewing hydrometeors in the field have often involved significant manual intervention and have been unpredictable and/or unreliable. In addition, past devices have not provided sufficient visualization of the more minute features of hydrometeors, such as the crystalline structure of snowflakes or ice, in a continuous fashion or in an accurate manner. None of these instruments have provided three-dimensional visualization.
The ability to accurately and dependably study various particles in the field, including hydrometeors, can be useful in a variety of applications. For example, ski resorts may use detailed imagery of snowflakes to generate public interest and to assess snowpack conditions. Detailed information of hydrometeor size, shape, mass and fall-speed can be used to develop improved precipitation parameterizations for weather and climate forecast models. Measurements of snowflake size and morphology can be used to improve avalanche forecast models. Being able to document and image hydrometeors and properties of the hydrometeors, particularly at close range, is potentially useful for a wide variety of applications. For example, improvements in systems can be useful for documenting and imaging hydrometeors, as well as for providing information on the oscillation of hydrometeors, the conditions at which the hydrometeors tumble, the specific type of crystals that traverse a point along a line of sight, and the relationship between fall speed and particle size, color data, volume data, fall speed, and trajectory.